Buck Knives: edge retention test

Sisal is some really tough stuff, but I can't help but wonder if the test would have turned out completely different if the task had been whittling soft pine, or slicing raw meat?
 
Thanks, Frank and Larry .
Joe, I've done the same type test on cutting meat many times and it render the same results while processing beef, chicken, elk and deer over the years . License meat cutters do it daily . They sharpen to the same grit as #1 . DM
 
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Most moderately equipped meat markets purchase for their meat cutters Norton's Tri-hone model IM-313 which holds three stones . The 100 grit coarse crystolon, a med. grit .240 crystolon and a 320 grit fine India . It is with these stones and grits that meat cutters sharpen their knives to make a living . I've talked with them many times about their knives while watching them sharpen . 320 grit will shave arm hair and cuts meat quickly giving good edge retention .No meat cutter I've met wished for any finer stone to sharpen on . DM
 
Why is a test of sawing rope an indication of anything other than the idea that larger serrations will tend to saw more quickly than smaller ones?

How can one draw conclusions on cutting performance when the test was on sawing performance?

Why should we be able to draw conclusions on "99% of our cutting needs" because of the sawing performance of a knife on rope?

ETA, I guess I should mention that the test, IMO, would be considerably more relevant if there were solid answers to these questions. It could be that I am simply missing the connection between sawing performance on rope and cutting performance on solid materials.
 
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I welcome your comments as any good test can stand up to scrutiny or slamming .
During these tests I also ran the results by Mr. Brendan James who at that time was a Product Specialist for Saint Gobain (Norton) . His comments were; " Using a coarser stone allows for micro-serrations to form on the blade . This, therefore, acts like a microscropic saw and will allow you to cut thru easily . Once you use 600 or 1000 grits you are polishing the edges of the blade and are effectively polishing away the edges of the micro-serration . This will leave the blade very sharp but not pratical for use in all situations ,"
Now, if you'll calm yourself, I even stated some other uses which a finer honed edge might be useful . Then I stated that I had found this same results on other mediums as well as licensed meat cutters . Conduct you own test making certain it can be duplicated and then you'll have a leg to stand on . DM
 
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DM, I am fine with the test. I have done testing on various mediums, though none will necessarily correlate with sisal rope, and have formed my own opinions. My point was simply that it was a test of sawing performance, which will obviously favor a serrated sawlike edge.

If your typical technique and mediums use a sawing motion, then obviously this type of edge would be the one for you. To indicate that it proves we should all be carrying micro-serrated edges is a bit of a stretch, however.

I prefer not to be required to saw with my blades, but if I ran the same test measuring pushcutting performance, obviously less sharp blades would show a very poor performance. It would be inaccurate to use that to show that we all need to be finishing to .5 micron or less, as once again, not all use technique and materials that would suit that type of finish.

If 320g edges could pushcut a variety of materials with the same efficiency as a properly sharpened edge, and last as long, I would be the first in line to adopt it.

If instead, they are simply a compromise, like everything else in the knife world, then it shows that like everything else, there is no 'right' answer.
 
OK, in order to make my point, I am going to present the test that I just performed, which, although the exact results would be unknown to me, seemed as if it would make an equally strong argument for a more refined edge.

I have a Cold Steel AK47, the older model, that is often heavily abused. It has a large hollow grind, and a fairly thin edge, so it is fairly easy to sharpen, and also has a very good profile for cutting.

I had abused it badly the other day, so there were portions of the edge hanging off, and 1 deep nick. I sharpened it on diamonds, first using extra coarse (220g, I think) and then moving to coarse, which I believe is 325.

For a test, I am pushcutting 1/2" poly rope, not truckers rope but the nicer feeling stuff that has a core in it. I would post pics but I am tired and it is late. Anyway, the results are as follows, which are an average of 5 or more cuts on a bathroom scale. All cuts are into wood, so the finer edge will suffer more from contact with the wood, which shows up towards the end.

325g finish--- 24lbs pressure. This was very consistent for 5 or 6 cuts. It cut lined paper adequately, but didn't sound sharp.

600g finish---19lbs pressure. This was slightly less consistent but ranged between 18-20, with most 18-19. This cut lined paper smoothly, and began to sound right.

1200g finish---18lbs pressure. I actually did this twice, because it didn't seem right. The difference was that the knife actually began cutting into the rope at @14lbs, but midway through the rope would begin to bunch and the pressure would rise. This edge would wisk through paper, and was just beginning to bite at hair above the skin.

My normal finish...1200g, UF Sharpmaker rod, and strop on green rouge then bare leather.---16lbs. pressure. This, like the last, was a bit different as the knife would begin cutting at @8lbs, but in the middle the pressure would rise to 16 or so. After multiple cuts into the wood, like 8 or so, pressures began to rise to @20lbs, I am assuming from blunting of the edge due to impact. I do need to mention that the final treatment on this edge was probably considerably less than optimal, as I was in a hurry.

What it seems like this shows is that while a rougher edge could conceivably used to cut, it requires considerably more force to do so. Using the 8lb figure where the sharpest edge began to cut, it required 1/3 of the force to make the cut. This is a huge difference in the amount of force that needs to be put on the knife, the strain on the knife, and the potential for injury between the two edges.

I guess my point would be that while one could use a coarse edge to cut with, unless there was a specific need,they may be better served by having a sharper knife.
 
If you cared to read those more knowledgable and hold more experience like, Joe Talmadge and John Juranitch in this subject you could make a better assessment of your test . You keep using 'sawing' I say its a slicing cut . Besides you don't push cut the hide off a deer nor does a housewife push cut up a chicken . DM
 
Well said DM,

Also, the blade industry standard is a CATRA test in which a knife is held stationary and a machine pulls/slices across the blade with constant measuable pressure with a stack of paper as the media. Based on how much of the paper stack it cuts through and subsequent reduction of amount of paper cut though use, edge retention is meausured. It doesnt matter that paper or anything else is used as long as it is the same for all blades being tested. Of course human pressure is not exact but still DM your test has to be considered perfectly valid.

here is a link showing a demonstration of the test equipment
http://www.youtube.com/watch?v=WpIRLMdWsiE

this is the test Buck uses
 
Thanks Ima for your considerations . There is two schools of thought on this and the two will remain seperate . Other than reading the more noteworthy writings of those I've mentioned who hold greater experience than any of us I'll give a third example and then be done discussing this subject . As we've reached a point of diminishing returns .
Last year I used a early 103 Skinner to gut, skin and quarter a 200lb. Mule deer . The blade steel was 440C which I sharpened to 800 grit (wanting to test a fine edge ) then stropped the daylights out of it . So, somewhere approaching 1K grit then took it to work on the deer . As I finished up the deer this knife was barely cutting and I was mostly forcing it to quarter the last leg . I then took the same knife back home, cleaned and sharpened it on a 280 grit Norton fine crystalline stone and went to work processing the meat . The knife now cut up and processed all the meat and was still cutting fine when I finished . So, I later used it to cut up a couple fryers and a 18 lb. brisket into the edible point cut and flat cut table fare . Processing requires more cutting out of the knife than field dressing so, draw your own conclusions . DM
 
DM, I am sorry for mentioning anything controversial in your thread. I honestly thought you would have had the ability to put up a little stronger defense, but, whatever. Enjoy your knives.
 
David,

Sorry, but seriously? You think this is a valid test to be able to make the claim that a coarse edge will satisfy 99% of sharpening needs, based on you sharpening one type of knife and slicing thru some rope? What if you added a serrated blade to the testing. Tried a different type of knife. Different steel. Different edge geometry. What would your conclusion be then?

I don't know about the others you mentioned, but you need to reread Juranitch's book. Better yet, get one of his fine hones he uses to finish a blade. He doesn't support this at all. In fact, here's a few quotes from his book (p.19):

"We have to confess when we were just getting started we thought the same thing" (You're supposed to have "teeth" on your edge). "As we got into our research though, the idea of teeth turned into nonsense." "If the edge was really sharp, we could see no teeth whatsoever."

"The fine hone is just the opposite" (of a coarse hone). "You want it as hard as possible, and the grit as fine as possible."

And from p.55. "Once that is accomplished,..." (setting the edge) "...you have to go to the other end of the rope to finish the edge. And how fine do you go? Just as fine as you can. It's not possible to go too fine." (Emphasis added by me.)

I also went and read Talmadge's sticky post. The only thing I could find related was this...

"Edge toothiness: Some steels seem to cut aggressively even when razor
polished. For these steels, even when they're polished for
push-cutting, their carbides form a kind of "micro serrations" and
slice aggressively."

I'd hardly call that a supporting claim. If anything, it shows why your testing is invalid. You don't even account for the steel.

All I can say is Wow. :confused: :eek: This is not a good test. All it is a test designed to support a conclusion you already had, if that. You could easily conclude that the edge wasn't properly refined, which, BTW is supported by the polished edge showing burring after 3 cuts. It would be easier to conclude it was improperly sharpened, explaining why it performed so poorly.

Good god, I actually tried to walk away from this, but I can't get it out of my head. What an awful test. The ONLY thing you can even remotely conclude is that: "David Martin gets the best performance on a V52 Selector blade sharpened on a Norton stone cutting 1/4" sisal rope, by leaving a very coarse edge on the blade." The fact that you didn't even attempt to eliminate any other factors means you really can't say anything else.

Don't take this personal 'cause it's not. It's just really really bad science. If you hadn't tried to generalize this to 99% of the rest of the world it wouldn't be a big deal. But the fact that you did, makes it really really wrong. Sure, it's one piece of the sharpening puzzle, and good info to have in that respect, but it's a very very small piece. Trying to add support from more knowlegeable sharpeners, Talmadge and Juranitch, (which turns out to not be very supportive), is a bit disingenuous.

cbw
 
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Perhaps there is some selective reading going on as John states in his book, pg.57 "you don't need more than a 400 grit to 600 plus your sharpening steel to get a great edge ."
Joe Talmadge states in his writing that in their tests they are getting great edge retention from knives sharpened very coarse . DM
 
OK, even that doesn't support your postion, since you claim a 280g edge is better than a 600g edge. Does he say anywhere that finishing an edge coarse vs. fine is better? That would be a supporting statement.

You'll have to link to what you're saying Talmadge says... I can't find it.

cbw
 
I know no one asked, but here's my $.02:

I have a Norton India Combination Bench Stone, Coarse/Fine. Fairly new.

I have a Norton AFB6. Probably around 30 years old - comparable to a soft arkansas, but better imho.

That's it - three (counting the combo as two) stones, and it gets my knives as sharp as I need them. Period. Do I know what grit they are? Nope. Do I care? Nope. Could I get my knives sharper by getting the latest, greatest stones or gadget? Probably. Do I care? Nope. Would they work on the latest, greatest wonder steel? Probably not. Do I care? Nope. They work on my knives, to my satisfaction ..... that is all I care about! :D
 
John's writing is favorable to my position because 400 grit is closer to the grit I use than your 1200 or 2000 . Then the Joe Talmadge article has changed its not the same one I reference as he mentioned Chad Ward conducted the tests and I could not find that writing . Still, what I'm hearing is no licensed meat cutter with 20-30yrs. experience can sharpen knives like you . They only have more carpal tunnel syndrome in one hand than many of us ever will from knife use and they don't know much ! Heck, my grandfathers should have died of starvation because to take the hide off a tough hog, steer or deer to stay alive they used low quality knives sharpened on low quality stones . How'd they ever do that ?? DM
 
cbwx34 said:
Finally, I wouldn't look to meat cutters as the pinnacle of sharpening knowledge....

cbw
Click to expand...

CBW, you just lost all credibility with that comment. I worked in a packing plant while going to college (albeit in the office, and not on the line), and if there is anyone I would hold up as having real world knowledge of sharpening, it's a meat cutter! Try standing on a fast moving line for 8 hours a day boning hams or cutting loins, and I guarantee if you don't know how to sharpen a knife when you start, you'll learn in a hurry. I would call that "the pinnacle of sharpening knowledge" ..... in the real world at least.
 
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